Synthesis and Crystal Structure of Methyl 2-(Diphenylamino)-4-phenyl-1,3-thiazole-5-carboxylate

The title compound, methyl 2-（diphenylamino）-4-phenyl-1,3-thiazole-5-carboxylate, was synthesized and studied by single-crystal X-ray diffraction method. The structure of the product was confirmed by IR, 1H- and 13C-NMR spectroscopy and elemental analysis. These experimental studies were supported by quantum mechanical calculations. The structure was solved in monoclinic, space group P21/c with a = 9.573（3）, b = 19.533（7）, c = 9.876（3）, β = 92.35（4）°, V = 1845.2（10）3, T = 85（2） K, Z = 4, R = 0.040 and wR = 0.089 for 6424 observed reflections with I2σ（I）.

How Effective Is the Single-point Energy Calculation in Investigating the Reaction Mechanisms?New Decarboxylation Mechanism of Pyrrole-2-carboxylic Acid by Full Optimization with CPCM Solvation Model

The decarboxylation of pyrrole-2-carboxylic acid in acid solutions was elucidated by full optimization with the CPCM solvation model at the B3LYP/6-31 l＋＋G（d,p） level. Compared with the single-point energy calculation, CPCM full optimization is better to model solvent environments to gain reasonable reaction mechanisms. The π interactions play a significant role in the decarboxylation of pyrrole-2-carboxylic acid （R）. Firstly, the a hydrogen is protonated, but all of the carbonyl hydration pathways bear relatively higher energy barriers. The carbonyl group can rove over the pyrrole ring, but it does not lead to the speciation of pyrrole and protonated carbon dioxide for the latter is an energy-rich species. The decarboxylation mechanism proposed here is that, the protonated pyrrole-2-carboxylic acid （RH） decarboxylates via direct C-C bond cleavage with the aid of a water molecule to accommodate the proton on the carbonyl group.

Synthesis,Structure,and Magnetic Property of One Snake-shaped Copper(Ⅱ)-organic Compound:Cu[Cu_2(PP)_2](CBPC)_2]·2(H_2O)

One novel copper（II）-organic compound,namely Cu[Cu2（PP）2]（CBPC）2]·2（H2O）（1,H2CBPC = 1-[（2＇-carboxybiphenyl-4-yl）methyl]-2-propylimidazole-4-carboxylic acid,HPP = 3-（2-pyridyl）pyrazole）,was designed and synthesized under hydrothermal conditions.X-ray diffraction analysis reveals that two Cu（II）ions in the quasi-planar dimmer of [Cu2（PP）2] are linked by the carboxylate oxygen atoms on the phenyl ring and the imidazole ring,respectively,yielding one snake-shaped structure.Magnetic measurements reveal that compound 1 shows the strongly antiferromagnetic property.Crystal data of 1：C58H52Cu3N10O10,Mr = 1239.72,monoclinic,P21/c,a = 14.900（7）,b = 15.029（7）,c = 12.308（6）,β = 102.519（9）o,V = 2691（2）3,Z = 2,Dc = 1.530 g/cm3,F（000）= 1274,μ = 1.246 mm-1,R = 0.0416,wR = 0.0780（I 2σ（I））and S = 0.999.

Hydrothermal Synthesis and Crystal Structure of One Novel 1-D Copper(Ⅱ)-organic Framework:{[Cu_2(PP)_2(CBPC)]_2·7H_2O}_n

One novel 1-D copper（Ⅱ）-organic compound,namely {[Cu2（PP）2（CBPC）]2·7H2O}n（1,H2CBPC=1-[（2＇-carboxybiphenyl-4-yl）methyl]-2-propylimidazole-4-carboxylic acid,HPP=3-（2-pyridyl）pyrazole）,was synthesized under hydrothermal conditions.X-ray diffraction analyses reveal that the two Cu（Ⅱ） ions in the distorted dimer [Cu2（PP）2] of 1 are linked by the carboxylate oxygen atoms on the phenyl and imidazole rings,respectively,forming one interesting snake-like chain.Single-crystal X-ray analyses reveal that it crystallizes in monoclinic,space group C2/c with a=30.656（8）,b=12.715（3）,c=22.405（5）,β=122.758（3）°,V=7344（3）3,Z=4,Mr=1681.65,Dc=1.521 g/cm3,F（000）=3464,μ=1.221 mm-1,the final R=0.0453 and wR=0.1023 for 4617 observed reflections with Ⅰ 〉2σ（Ⅰ）.

Synthesis and Quantum Chemistry Studies of (R)-N-(Propionylthiazolidine-2-thione-4-methoxycarbonyl)germanium Sesquioxide

(R)-N-(β-Trichlorogermyl propionyl)thiazolidine-2-thione-4-carboxylic methyl ether(1) and its sesquioxide(2) were synthesized. The crystal structure of 1 was determined by means of X-ray diffraction analysis, which shown that the >CO and >CS groups are located in the opposite sides of C(4)—N—C(3) bond with transconfiguration. The electronic structures and optimized configurations of compounds 1 and 2 were studied with MNDO method.

Density functional theory study of the mechanism of the acid-catalyzed decarboxylation of pyrrole-2-carboxylic acid and mesitoic acid

The mechanisms of the acid-catalyzed decarboxylation of pyrrole-2-carboxylic acid and mesitoic acid have been investigated based on density functional theory calculations at the B3LYP/6-311G (d,p) level. A polarizable continuum model (PCM) has been established in order to evaluate the effects of solvents on these reactions. The results of the calculations indicate that the first step of the acid-catalyzed decarboxylation of the pyrrole-2-carboxylic acid has two possible pathways,that is,the proton of H3O+ attacks either the-carbon atom or the carboxyl oxygen atom. The subsequent process of forming a four-membered ring transition state is the rate-determining step. The activation energies of acid-catalyzed decarboxylation of pyrrole-2-carboxylic acid proceeding via attack at the-carbon atom and the carboxyl oxygen atom are determined to be 194.21 and 210.41 kJ/mol,respectively. The computational results show that both pathways are favored. However,for the reaction of mesitoic acid with H3O+,the reaction barrier for the former pathway is calculated to be 212.15 kJ/mol,whilst the latter pathway has a reaction barrier of 200.45 kJ/mol. Our computational results are consistent with the experimental observations of Mundle and Kluger.

<i>Streptomyces zerumbet</i>, a Novel Species from <i>Zingiber zerumbet</i>(L.) Smith and Isolation of Its Bioactive Compounds

Streptomyces zerumbet W14, a novel species of the endophyte genus Streptomyces was isolated from the rhizome tissue of Zingiber zerumbet (L.) Smith. Identification of strain W14 was based on its morphology, chemotaxonomy and phylogenetic analysis using 16S rDNA sequence. It was classified as the secondary meabolites of the culture extract were studied. The major active ingredients from the crude extract were purified by silica gel column chromatography and identified by spectroscopic data. The crude extract and purified compounds were tested for their biological activities on antibacterial and anti-inflammatory properties. The crude extract showed inhibition on the growth of Gram-positive bacteria with the MIC and MBC values of 8 - 32 μg/ml and 32 - 128 μg/ml, respectively. The isolated compounds were identified to be methyl 5-(hydroxymethyl)furan-2-carboxylate (1) and geldanamycin (2). Bioassay studies showed that compound 1 had antibacterial activity against Staphylococus aureus ATCC 25923 and Methicillin Resistant S. aureus strain Sp6 (clinical isolate) with the MIC and MBC values of 1 μg/ml and 16 - 64 μg/ml, respectively, and also showed activity against Bacillus Calmette-Guérin (vaccine strain) with MIC and MBC values of 128.00 μg/ml and 128.00 μg/ml, respectively. The compound 2 at the concentration of 1 - 5 μg/ml had in vitro anti-inflammatory activity on LPS-induced RAW 264.7 cells by inhibition of mRNA expression and production of inducible NO synthase (iNOS), tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). These results suggest that compounds 1 and 2 produced by S. zerumbet W14 (an endophyte of Z. Zerumbet) have antibacterial and anti-inflammatory activities, respectively. Therefore, the future studies on these compounds could be useful for the management of bacterial infections and inflammatory diseases.